ONGOING SCANNING ELECTRON MICROSCOPY AND BULK CHEMICAL INVESTIGATIONS OF ROAD SEDIMENT ASSOCIATED WITH A PETROCHEMICAL PLANT IN PENUELAS, PUERTO RICO

Petrochemical plants are large, complex entities that may distribute an array of materials associated with petrochemical production into the environment, and thus are of significant environmental concern. One readily accessible environmental medium that may provide insight into the distribution and composition of pollution associated with petrochemical plants is road sediment. Road sediment in regard to petrochemical plants specifically has not been extensively studied in the U.S. One understudied region in the U.S in this context is Penuelas, Puerto Rico. Geogenic background in this region consists mainly of marine volcaniclastic rocks, limey sedimentary rocks, and carbonate sands. Six sets of triplicate road sediment samples were collected with increasing distance from the petrochemical plant (n=18) for scanning electron microscopy - energy dispersive spectroscopy (SEM-EDS) and inductively coupled plasma - mass spectrometry (ICP-MS) analysis. Initial SEM-EDS data reveals the metals Fe, Mn, Ni, Cr, Cu, Ag, Zn, W, Ba, and V in a large variety of forms, as well as a variety of degraded technogenic spherules of varying sizes and compositions. Several particles are chemically consistent with steel alloys (e.g., Fe, Ni, Cr), and exhibit fine textures indicative of local sourcing. Presently, it is unclear if these materials can be traced to specific anthropogenic origins. Ba is commonly present in the form of BaSO4 with crushed, angular morphologies, likely originating from white road paint. ICP-MS analysis is ongoing, and may offer insight into chemical composition patterns, or lack thereof, with varying distance from the plant. This analysis opens several questions in regard to the distinction between anthro- and geogenic origins within road sediment, as well as evaluation of potential environmental and human health impacts associated with metal exposure from road sediment.